<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>level 6</title>
</head>
<body>
level 6<br>
goL elosnoC lmth.niam\eno.icic<br>
hint:前8个字符
<input id="in" type="text"> <button onclick="submit()">提交</button>
<script>
  function submit(){
    var val=document.getElementById('in').value;
    var vb=btoa(val);
    alert(vb);
  }
</script>
</body>
</html>